Fluorine-containing monomeric ester compound for base resin in photoresist composition

Abstract

The invention discloses a novel ester compound of an unsaturated carboxylic acid represented by the general formula in which R 1 is preferably a hydrogen atom or methyl group, R 2 is preferably a trifluoromethyl group, R 3 is a non-aromatic polycyclic hydrocarbon group or, preferably, an adamantyl group and R 4 is preferably a hydrogen atom or methyl group. This unsaturated ester compound is polymerizable to give a (co)polymeric resin which can be used as a base resinous ingredient in a photoresist composition for light exposure with ultraviolet light of a very short wavelength by virtue of the high transparency to the short-wavelength light. A synthetic method for the preparation of the novel ester compound is disclosed.

1. A fluorine-containing ester compound of an unsaturated carboxylic acid represented by the general formula 
                 
 
       in which R 1  is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms or a fluoroalkyl group having 1 to 4 carbon atoms, R 2  is a fluorine atom or a fluoroalkyl group having 1 to 4 carbon atoms, R 3  is a non-aromatic polycyclic hydrocarbon group and R 4  is a hydrogen atom, a fluorine atom, an alkyl group having 1 to 4 carbon atoms or a fluoroalkyl group having 1 to 4 carbon atoms. 
     
     
       2. The fluorine-containing ester compound of an unsaturated carboxylic acid as claimed in  claim 1  wherein R 1  is a hydrogen atom, R 2  is a fluoroalkyl group having 1 to 4 carbon atoms, and R 4  is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 
     
     
       3. The fluorine-containing ester compound of an unsaturated carboxylic acid as claimed in  claim 1  wherein R 1  is a methyl group, R 2  is a fluoroalkyl group having 1 to 4 carbon atoms and R 4  is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.